Conventionally, a membrane electrode assembly (hereinafter referred to as an MEA) for a fuel cell has an electrolyte membrane having ionic conductivity and a pair of gas diffusion electrodes having gas diffusivity and electric conductivity bonded to both sides in thickness direction of the electrolyte membrane. When electricity is being generated, fuel is supplied to one of the gas diffusion electrodes, and oxidant is supplied to the other of the gas diffusion electrodes.
JP2003-234106A describes a technique for pressing, by means of a pressing machine, each of the gas diffusion electrodes before it is bonded to an electrolyte membrane. JP2003-234106A further describes that by the use of this technique surfaces of each of the gas diffusion electrodes are protected from flix by the use of this technique.
JP06(1994)-338335A describes a fuel cell including a membrane electrode assembly having an electrolyte membrane and gas diffusion electrodes bonded to both sides of the electrolyte membrane in a thickness direction. According to this fuel cell, curves are provided at corners of the tetragonal gas diffusion electrodes in plane view of the gas diffusion electrodes. JP1994-338335A further describes that even when an electrolyte membrane is caused to shrink, the electrolyte membrane is protected from damage.
As described above, the MEA has the electrolyte membrane having ionic conductivity and the pair of gas diffusion electrodes having gas diffusivity and electric conductivity bonded to both sides of the electrolyte membrane in a thickness direction thereof. For the MEA described above, a further improvement in quality of the fuel cell is required, further improvements in durability and longevity of the electrolyte membrane are accordingly required.
A need thus exists for a membrane electrode assembly for a fuel cell with further improved durability and further improved longevity of the electrolyte membrane, and a fuel cell. The present invention has been made in view of the above circumstances, and provides such an electrolyte membrane assembly for a fuel cell, and a fuel cell.